rufusbooth
1/2 ton status
Yep! gear vendors is out. it will only work 2wd.
CK5
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Manual Shift 6 speed 4L80E
- Thread starter Dr. Custom Werx
- Start date
Yep! gear vendors is out. it will only work 2wd.
pseudomike
1/2 ton status
I understand completely what you are trying to do. And back in the 90's JET made a valve body to accomplish this much cheaper than the TCI setup but unpopular because it was manual shift like you are looking for. It was $1200.
Now if you want to get down to it the 4L80E is capable of 6 shifts because it has 3 separate planetary gear sets. All you need is a valve body that can make 2 event shifts IE splits the 3 gears with the OD. 1st -->1st OD (2nd)-->2nd (3rd)-->2nd OD (4th)-->3rd (5th)--> 3rd OD (6th).
So you need a valve body to accomplish this. I have no insight here. I would probably try to find a JET kit someone bought.
Now if you want to get down to it the 4L80E is capable of 6 shifts because it has 3 separate planetary gear sets. All you need is a valve body that can make 2 event shifts IE splits the 3 gears with the OD. 1st -->1st OD (2nd)-->2nd (3rd)-->2nd OD (4th)-->3rd (5th)--> 3rd OD (6th).
So you need a valve body to accomplish this. I have no insight here. I would probably try to find a JET kit someone bought.
cabledawg
Secret Squirrel
http://www.syty.net/forums/showthread.php?t=68144
Here is something about a switch pitch TC used on a TH400 trans to essentially get 6 forward and 2 reverse gears out of a 3-spd trans. I dont know much about older cars to know all the lingo, but its a good read.
Here is something about a switch pitch TC used on a TH400 trans to essentially get 6 forward and 2 reverse gears out of a 3-spd trans. I dont know much about older cars to know all the lingo, but its a good read.
pseudomike
1/2 ton status
The idea is that a 4L80E lockup converter would function similarly if you could figure out how to control it. i would think it would be 'funny' to drive No Lockup -> Lockup -> No lockup -> lockup so on.
cabledawg
Secret Squirrel
Dr. Custom Werx
Registered Member
thank you! that is pretty much what i have determined. i wonder if the valve body can just be modified to manual like most other transmissions to do the 6 speed move
pseudomike
1/2 ton status
Transgo makes a manual kit for the 4L80E. It's a couple hundred bucks. I helped a friend install one in a 4L80E conversion because he did not want to pony up for a controller. It is still only 4 gears though. You need to to figure out how to activate the lockup between gears to get the full 6 speeds. This is where I do not know enough about the internal workings of the 4L80E to help you. I understand the theory and that it should be possible I just don't know exactly what it will entail to accomplish it.
It's just a valve body. An electric controlled VB at that. It's just a matter of figuring out which solenoids to power up/power down at what times. NOW, with that said, I don't know if the solenoids are straight 12v on/off or if they are pulse width modulated via a trans control module. I would assume straight 12v but they could use PWM to soften the shifts.
And I think what we want to know is, Why would you want to have 6 speeds instead of the 4, what advantage are you looking for? Or was it just a question to see if the possibilty exists.
Dr. Custom Werx
Registered Member
i want 6 speeds over 4 for the same reasons most would and a 700r4 over a 2 speed powerglide. im not trying to figure out if the possibility exists because its has already been proven to work. what im looking for is how to do it. i am working with someone right now and we have the wiring/hydraulic diagrams that look very simple. i think it will end up being very cheap and easy to do this but it would have to be a push button shifter for now.
Sorry, didn't mean to come of sounding like I was questioning your wants. If you want to build it then go for it. I wish I had something to offer in that area.
Dr. Custom Werx
Registered Member
its cool man. no worries. i just didnt want the thread to get too far off topic.
Can anyone give me a quick description of what the "Force Motor" does in a 4L80E? looks like as soon as i know what that does ill know how to shift all 6 different ratios. the only thing left would be for me cross that with the hydraulic diagrams and make sure the fluid goes where it needs to be going in every gear.
Can anyone give me a quick description of what the "Force Motor" does in a 4L80E? looks like as soon as i know what that does ill know how to shift all 6 different ratios. the only thing left would be for me cross that with the hydraulic diagrams and make sure the fluid goes where it needs to be going in every gear.
The trans will still be a 4 speedo auto, basically all you are doing is manually turning the lock-up convertor on/off. When the convertor locks up the RPM's will drop about 300 RPM or so. Most OD transmissions will lock up the convertor in 2,3,and 4th so in essence you would have 7 "ranges". You would have 1st, 2nd, 2nd lock-up, 3rd, 3rd lock-up, 4th, 4th lock-up. My buddy that owns a trans shop did this to a van that they used for towing about 15 years ago. The only problem is that if you get into 4th gear and forget to lovk the convertor and allow it to continue slipping it will build alot of heat and kill the trans.
any reason you cant lock up in first?? having that split would be nice
I like the idea of splitting every gear keeps the engine closer to its peak torque
I like the idea of splitting every gear keeps the engine closer to its peak torque
pseudomike
1/2 ton status
The JET kit split every gear. Look in my previous post, that was the order. I remember reading somewhere that some 4L80E were PWM and some were not. You might be able to figure it out by the model year break in the torque converter application.
pseudomike
1/2 ton status
The force motor solenoid is a TCM-controlled device used to regulate transmission line pressure. The TCM compares TP voltage, engine rpm and other inputs to determine the appropriate line pressure of a given load. The TCM will regulate the pressure by applying a varying amperage to the pressure control solenoid. The applied amperage can vary from 0.1 to 1.1 amp. The TCM then monitors the amperage at the return line. DTC 73 Will Set When: . The return amperage varies greater than 0.16 amps from the commanded amperage. . All conditions are met for 1 second
I've heard the idea before that adding a lockup converter is like "adding an overdrive", but of course it really isn't. And that's not what this modification is. You can't advertise lock/unlock as specific gear ratios...
From their website:
It looks like the extra planetary set is an added OD of 0.75 (isn't 4L80E basically a TH400 with an OD added?). If you multiply 1st and 2nd by that number, you see their two new ratios (2.23 and 1.18). As for lockup, it should be available in any gear that it was available in before, plus the "overdrive" version of that gear. Maybe the TCM has direct control and lockup is available in any gear. Without knowing anything about the torque ratings, I would worry about the strength of the OD gearset behind 1st gear, but they are rating it for 850hp. It doesn't say anything about custom planetaries.
As for building your own controller - don't assume this is easy! How do you control the line pressure? How do you apply and release the TCC? Isn't it PWM modulated to a specific curve for apply and release? Can the solenoids even be controlled by 12VDC or are they supposed to be pulsed?
Dr. Custom Werx
Registered Member
im not talking about anything to do with locking up the converter.
pseudomike
1/2 ton status
That is how I read it. As I stated earlier, the 4L80-E has 3 planetary sets. That is 3 speeds. It also has an OD planetary set making four speeds. So if you do the math there you have 6 speeds without using the lockup converter. Realistically you could have 8 speeds if you did incorporate the lockup but I would not consider the extra 2 as gears. Think of it as similar to the old Chrysler A518's with the huge OD unit on the back. 3 forward gears + OD (not lockup OD). If you could engage that OD planet between gears you essentially split the gear.
I think guys are confusing it with the 4L60E and 700R4 which only have 2 planetary gear sets. You could not get six speeds out of the 4L60E/700R4 transmissions without using lockup. Hopefully that clarifies it.
I wish I could point this guy in the right direction but I am not a transmission "guy". I have rebuilt my own and understand the internal components but no clue how to modify it. i am very interested in seeing what he comes up with.
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pseudomike
1/2 ton status
Tombirch.com has a LOT of GM transmission info but I did not find any 4L80E stuff.
